Pub Date : 2001-01-21DOI: 10.1109/MEMSYS.2001.906475
P. Griss, P. Enoksson, G. Stemme
We fabricated and tested two types of microstructures for the mechanical attachment of chips to soft surfaces. The microstructures are barbed spikes etched in silicon using DRIE (Deep Reactive Ion Etching). The mechanical attachment of two types of barbed spike arrays was measured on nonbiological materials (Polyethylene foil, Aluminium foil and Parafilm/sup TM/) as well as on human skin. The maximum adhesion force was 1,36 N achieved by a 2/spl times/2 mm/sup 2/ chip containing 64 barbed spikes pressed in Polyethylene foil. Maximum adhesion in skin was 0,54 N. The shape of the two different barb types has significant influence on the detachment forces for nonbiological materials.
{"title":"Barbed spike arrays for mechanical chip attachment","authors":"P. Griss, P. Enoksson, G. Stemme","doi":"10.1109/MEMSYS.2001.906475","DOIUrl":"https://doi.org/10.1109/MEMSYS.2001.906475","url":null,"abstract":"We fabricated and tested two types of microstructures for the mechanical attachment of chips to soft surfaces. The microstructures are barbed spikes etched in silicon using DRIE (Deep Reactive Ion Etching). The mechanical attachment of two types of barbed spike arrays was measured on nonbiological materials (Polyethylene foil, Aluminium foil and Parafilm/sup TM/) as well as on human skin. The maximum adhesion force was 1,36 N achieved by a 2/spl times/2 mm/sup 2/ chip containing 64 barbed spikes pressed in Polyethylene foil. Maximum adhesion in skin was 0,54 N. The shape of the two different barb types has significant influence on the detachment forces for nonbiological materials.","PeriodicalId":311365,"journal":{"name":"Technical Digest. MEMS 2001. 14th IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.01CH37090)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130915576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-01-21DOI: 10.1109/MEMSYS.2001.906560
M. Krishnan, S. Brahmasandra, D. T. Burke, C. Mastrangelo, M. Burns
Heat-transfer considerations significantly constrain design of multiple reaction microdevices. We present a new methodology for design and fabrication of multiple reaction systems using the concept of heat integration. Heat integration is a design concept that strikes a balance between complete thermal isolation of individual thermal operations and power consumption in a multiple reaction device. It relies on the use of steady-state temperature gradients developed in the substrate, by the actuation of a single reaction chamber, to initiate several reactions at progressively lower temperatures. The use of thermal gradients in this manner eliminates power requirements to heat individual reactions, active temperature control of "passive" reaction chambers and power requirement for cooling. Complete thermal isolation on the other hand, requires higher power for device cooling but, unlike the case of heat integration, geometry of component placement is relatively unconstrained.
{"title":"Design of multiple reaction systems for genetic analysis","authors":"M. Krishnan, S. Brahmasandra, D. T. Burke, C. Mastrangelo, M. Burns","doi":"10.1109/MEMSYS.2001.906560","DOIUrl":"https://doi.org/10.1109/MEMSYS.2001.906560","url":null,"abstract":"Heat-transfer considerations significantly constrain design of multiple reaction microdevices. We present a new methodology for design and fabrication of multiple reaction systems using the concept of heat integration. Heat integration is a design concept that strikes a balance between complete thermal isolation of individual thermal operations and power consumption in a multiple reaction device. It relies on the use of steady-state temperature gradients developed in the substrate, by the actuation of a single reaction chamber, to initiate several reactions at progressively lower temperatures. The use of thermal gradients in this manner eliminates power requirements to heat individual reactions, active temperature control of \"passive\" reaction chambers and power requirement for cooling. Complete thermal isolation on the other hand, requires higher power for device cooling but, unlike the case of heat integration, geometry of component placement is relatively unconstrained.","PeriodicalId":311365,"journal":{"name":"Technical Digest. MEMS 2001. 14th IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.01CH37090)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125355230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-01-21DOI: 10.1109/MEMSYS.2001.906607
G. Lammel, S. Schweizer, P. Renaud
We present a MEMS infrared spectrometer for selective and quantitative chemical gas analysis. Infrared absorption spectroscopy can distinguish gases easily and also detect nonreactive molecules like CO/sub 2/, in contrast to e.g. metal oxide gas sensors. The following new spectrometer concept avoids expensive linear detectors as used for grating spectrometers: A tunable interference filter scans the desired part of the infrared spectrum. A single pixel thermopile detector measures serially the intensify at selected wavelengths. The tunable optical interference filter is fabricated by a new porous silicon batch technology using only two photolithography steps. The refractive index of this filter microplate is gradually modulated in depth to create a Bragg mirror, edge filter or a Fabry-Perot bandpass filter for central wavelengths between 400 nm and 8 /spl mu/m. Two thermal bimorph micro-actuators tilt the plate by up to 90/spl deg/, changing the incidence angle of the beam to be analyzed. This tunes the wavelength transmitted to the detector. The filter area can be chosen between 0.27 mm/spl times/0.70 mm and 2.50 mm/spl times/3.00 mm, its thickness is typically 30 /spl mu/m. The spectral finesse /spl lambda///spl Delta//spl lambda/ of 25 is sufficient for most diagnosis applications. First results showed that CO/sub 2/ and CO can be detected selectively with this system-which is interesting in combustion processes-by measuring their absorption at 4.26 /spl mu/m and 4.65 /spl mu/m respectively. Other wavelength ranges e.g. for liquid analysis or colorimetry of visible light are possible.
{"title":"MEMS infrared gas spectrometer based on a porous silicon tunable filter","authors":"G. Lammel, S. Schweizer, P. Renaud","doi":"10.1109/MEMSYS.2001.906607","DOIUrl":"https://doi.org/10.1109/MEMSYS.2001.906607","url":null,"abstract":"We present a MEMS infrared spectrometer for selective and quantitative chemical gas analysis. Infrared absorption spectroscopy can distinguish gases easily and also detect nonreactive molecules like CO/sub 2/, in contrast to e.g. metal oxide gas sensors. The following new spectrometer concept avoids expensive linear detectors as used for grating spectrometers: A tunable interference filter scans the desired part of the infrared spectrum. A single pixel thermopile detector measures serially the intensify at selected wavelengths. The tunable optical interference filter is fabricated by a new porous silicon batch technology using only two photolithography steps. The refractive index of this filter microplate is gradually modulated in depth to create a Bragg mirror, edge filter or a Fabry-Perot bandpass filter for central wavelengths between 400 nm and 8 /spl mu/m. Two thermal bimorph micro-actuators tilt the plate by up to 90/spl deg/, changing the incidence angle of the beam to be analyzed. This tunes the wavelength transmitted to the detector. The filter area can be chosen between 0.27 mm/spl times/0.70 mm and 2.50 mm/spl times/3.00 mm, its thickness is typically 30 /spl mu/m. The spectral finesse /spl lambda///spl Delta//spl lambda/ of 25 is sufficient for most diagnosis applications. First results showed that CO/sub 2/ and CO can be detected selectively with this system-which is interesting in combustion processes-by measuring their absorption at 4.26 /spl mu/m and 4.65 /spl mu/m respectively. Other wavelength ranges e.g. for liquid analysis or colorimetry of visible light are possible.","PeriodicalId":311365,"journal":{"name":"Technical Digest. MEMS 2001. 14th IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.01CH37090)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116969329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-01-21DOI: 10.1109/MEMSYS.2001.906542
Y. Yee, J. Bu, Man-Hyo Ha, Junghoon Choi, Hyun-Ah Oh, Sangshin Lee, H. Nam
An actuated micromirror having two-degree of freedom in rotational motion around the orthogonal axes is designed and fabricated. Suspended unimorph PZT actuators independently control the rotation of the micromirror along the two perpendicular axes. The PZT actuators located symmetrically around the axes of the actuation are mechanically isolated with each other during their operation by a gimbaled structure. The mechanical cross talk between each axis of actuation is well suppressed less than 7% due to the gimbals. The rotation angle /spl theta/ of the micromirror reaches 0.75/spl deg/ under the applied bias of 15 V while maintaining the profile of the reflected laser beam without significant degradation.
{"title":"Fabrication and characterization of a PZT actuated micromirror with two-axis rotational motion for free space optics","authors":"Y. Yee, J. Bu, Man-Hyo Ha, Junghoon Choi, Hyun-Ah Oh, Sangshin Lee, H. Nam","doi":"10.1109/MEMSYS.2001.906542","DOIUrl":"https://doi.org/10.1109/MEMSYS.2001.906542","url":null,"abstract":"An actuated micromirror having two-degree of freedom in rotational motion around the orthogonal axes is designed and fabricated. Suspended unimorph PZT actuators independently control the rotation of the micromirror along the two perpendicular axes. The PZT actuators located symmetrically around the axes of the actuation are mechanically isolated with each other during their operation by a gimbaled structure. The mechanical cross talk between each axis of actuation is well suppressed less than 7% due to the gimbals. The rotation angle /spl theta/ of the micromirror reaches 0.75/spl deg/ under the applied bias of 15 V while maintaining the profile of the reflected laser beam without significant degradation.","PeriodicalId":311365,"journal":{"name":"Technical Digest. MEMS 2001. 14th IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.01CH37090)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132399191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-01-21DOI: 10.1109/MEMSYS.2001.906556
C. Ho
Microfluidics is a collection of processes for moving bulk fluid mass or controlling the paths of selected embedded particles, cells or molecules, in flows. Length scale matching between the flow and the device is the key for efficient momentum and energy transfers of the desired fluid motions. MEMS enable us to handle minute amounts of fluid in the nano or pico liter range. With properly designed microfluidic devices, molecules can be directly manipulated by the flow patterns inside the device, which provides a pathway to exploit the nano world. Obviously, understanding of the molecular effects on flows becomes a crucial issue. In traditional fluid dynamics, the flow length scale is much larger than the molecular length scale. Continuum is the most common hypothesis for flow researches. In the case of micro/nano engineering system, we are in the transition regime between continuum and molecule dominated conditions. This feature brings us the challenges when exploring the science and developing the technology in micro/nano fluidics.
{"title":"Fluidics-the link between micro and nano sciences and technologies","authors":"C. Ho","doi":"10.1109/MEMSYS.2001.906556","DOIUrl":"https://doi.org/10.1109/MEMSYS.2001.906556","url":null,"abstract":"Microfluidics is a collection of processes for moving bulk fluid mass or controlling the paths of selected embedded particles, cells or molecules, in flows. Length scale matching between the flow and the device is the key for efficient momentum and energy transfers of the desired fluid motions. MEMS enable us to handle minute amounts of fluid in the nano or pico liter range. With properly designed microfluidic devices, molecules can be directly manipulated by the flow patterns inside the device, which provides a pathway to exploit the nano world. Obviously, understanding of the molecular effects on flows becomes a crucial issue. In traditional fluid dynamics, the flow length scale is much larger than the molecular length scale. Continuum is the most common hypothesis for flow researches. In the case of micro/nano engineering system, we are in the transition regime between continuum and molecule dominated conditions. This feature brings us the challenges when exploring the science and developing the technology in micro/nano fluidics.","PeriodicalId":311365,"journal":{"name":"Technical Digest. MEMS 2001. 14th IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.01CH37090)","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133070176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-01-21DOI: 10.1109/MEMSYS.2001.906567
J. Burger, H. Holland, E. Berenschot, J. Seppenwoolde, M. ter Brake, H. Gardeniers, M. Elwenspoek
This paper presents the first cryogenic micromachined cooler that is suitable to cool from ambient temperature to 169 kelvin and below. The cooler operates with the vapor compression cycle. It consists of a silicon micromachined condenser, a flow restriction/evaporator and two miniature glass-tube counterflow heat exchangers, which are integrated with the silicon components using a novel gluing technique. The system was tested with ethylene gas from 20 to 1 bar, and produces a cooling power of 200 mW at 169 K with a mass flow of 0.5 mg/s.
{"title":"169 kelvin cryogenic microcooler employing a condenser, evaporator, flow restriction and counterflow heat exchangers","authors":"J. Burger, H. Holland, E. Berenschot, J. Seppenwoolde, M. ter Brake, H. Gardeniers, M. Elwenspoek","doi":"10.1109/MEMSYS.2001.906567","DOIUrl":"https://doi.org/10.1109/MEMSYS.2001.906567","url":null,"abstract":"This paper presents the first cryogenic micromachined cooler that is suitable to cool from ambient temperature to 169 kelvin and below. The cooler operates with the vapor compression cycle. It consists of a silicon micromachined condenser, a flow restriction/evaporator and two miniature glass-tube counterflow heat exchangers, which are integrated with the silicon components using a novel gluing technique. The system was tested with ethylene gas from 20 to 1 bar, and produces a cooling power of 200 mW at 169 K with a mass flow of 0.5 mg/s.","PeriodicalId":311365,"journal":{"name":"Technical Digest. MEMS 2001. 14th IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.01CH37090)","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133373591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-01-21DOI: 10.1109/MEMSYS.2001.906478
H. Takagi, R. Maeda, T. Suga
A room-temperature wafer bonding method between dissimilar materials is developed. 4-inch Si wafers and 3 or 4-inch ceramic wafers are bonded in vacuum after surface sputter etching by Ar beam. Strong bonding equivalent to bulk material is achieved by room-temperature process. The method enables the bonding between dissimilar materials regardless the thermal expansion mismatch and crystal lattice mismatch. In addition, it also realizes very low damage bonding because it does not require any heating process and external load to force two specimens together.
{"title":"Wafer-scale room-temperature bonding between silicon and ceramic wafers by means of argon-beam surface activation","authors":"H. Takagi, R. Maeda, T. Suga","doi":"10.1109/MEMSYS.2001.906478","DOIUrl":"https://doi.org/10.1109/MEMSYS.2001.906478","url":null,"abstract":"A room-temperature wafer bonding method between dissimilar materials is developed. 4-inch Si wafers and 3 or 4-inch ceramic wafers are bonded in vacuum after surface sputter etching by Ar beam. Strong bonding equivalent to bulk material is achieved by room-temperature process. The method enables the bonding between dissimilar materials regardless the thermal expansion mismatch and crystal lattice mismatch. In addition, it also realizes very low damage bonding because it does not require any heating process and external load to force two specimens together.","PeriodicalId":311365,"journal":{"name":"Technical Digest. MEMS 2001. 14th IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.01CH37090)","volume":"146 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116511765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-01-21DOI: 10.1109/MEMSYS.2001.906469
T. Kawai, K. Sawada, Y. Takeuchi
A variety of microstructures with high accuracy were introduced by means of mechanical machining technology, using the authors' super-nano friction free machine.
利用自制的超纳米无摩擦机床，通过机械加工技术，引入了各种高精度的显微组织。
{"title":"Ultra-precision micro structuring by means of mechanical machining","authors":"T. Kawai, K. Sawada, Y. Takeuchi","doi":"10.1109/MEMSYS.2001.906469","DOIUrl":"https://doi.org/10.1109/MEMSYS.2001.906469","url":null,"abstract":"A variety of microstructures with high accuracy were introduced by means of mechanical machining technology, using the authors' super-nano friction free machine.","PeriodicalId":311365,"journal":{"name":"Technical Digest. MEMS 2001. 14th IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.01CH37090)","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114606486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-01-21DOI: 10.1109/MEMSYS.2001.906578
H. Dirac, P. Gravesen
We here report on the realisation of all liquid optical waveguides (ALOW). To our knowledge this is the first report in the literature on this topic. ALOWs are fluidic structures with waveguiding properties. They are realised in flow channels or tubes under laminar flow conditions, i.e. at moderate Reynolds numbers. The ALOW consists of an annular flow of two liquids, where the centre core liquid has a higher refractive index than the surrounding cladding liquid. The main applications for ALOWs are in optical detection.
{"title":"Realisation and characterisation of all liquid optical waveguides","authors":"H. Dirac, P. Gravesen","doi":"10.1109/MEMSYS.2001.906578","DOIUrl":"https://doi.org/10.1109/MEMSYS.2001.906578","url":null,"abstract":"We here report on the realisation of all liquid optical waveguides (ALOW). To our knowledge this is the first report in the literature on this topic. ALOWs are fluidic structures with waveguiding properties. They are realised in flow channels or tubes under laminar flow conditions, i.e. at moderate Reynolds numbers. The ALOW consists of an annular flow of two liquids, where the centre core liquid has a higher refractive index than the surrounding cladding liquid. The main applications for ALOWs are in optical detection.","PeriodicalId":311365,"journal":{"name":"Technical Digest. MEMS 2001. 14th IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.01CH37090)","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117342897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-01-21DOI: 10.1109/MEMSYS.2001.906464
H. Reichl, V. Grosser
Micro Electro Mechanical Systems (MEMS) packaging is expensive and product and application specific. Single chip packages for IC's are only for some microsystems applicable. Cost efficient MEMS packaging focuses wafer level packaging (WLP). An identical trend is observed in IC packaging. Chip size packages (CSP) are fabricated by WLP. Future microelectronic system will be fabricated by wafer level assembly of multiple components on a base chip. System on package (SOP) techniques including 3D cubic integration will be used. For MEMS packaging a Modular MEMS system integration (MOMEMS) is proposed. Cubic integration by stacking of CSP packaged MEMS modules contribute to an economic realization of low volume microsystems.
{"title":"Overview and development trends in the field of MEMS packaging","authors":"H. Reichl, V. Grosser","doi":"10.1109/MEMSYS.2001.906464","DOIUrl":"https://doi.org/10.1109/MEMSYS.2001.906464","url":null,"abstract":"Micro Electro Mechanical Systems (MEMS) packaging is expensive and product and application specific. Single chip packages for IC's are only for some microsystems applicable. Cost efficient MEMS packaging focuses wafer level packaging (WLP). An identical trend is observed in IC packaging. Chip size packages (CSP) are fabricated by WLP. Future microelectronic system will be fabricated by wafer level assembly of multiple components on a base chip. System on package (SOP) techniques including 3D cubic integration will be used. For MEMS packaging a Modular MEMS system integration (MOMEMS) is proposed. Cubic integration by stacking of CSP packaged MEMS modules contribute to an economic realization of low volume microsystems.","PeriodicalId":311365,"journal":{"name":"Technical Digest. MEMS 2001. 14th IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.01CH37090)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122298195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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